1. Field of the Invention
The invention relates to the field of spray washing objects on a conveyor system, and in particular to high-pressure spray washing of citrus fruit in a brush bed conveyor system.
2. Description of the Prior Art
It is well known to wash or spray objects, such as fruit or more particular citrus fruit, in conveyor systems from a fixed overhead spray manifold as the objects are being scrubbed or cleaned in a conveyor brush bed. The purpose for washing the citrus fruit may include, for example, not only removal of field dirt, contaminants and pesticides, but also, particularly in the case of high-pressure spraying, removal of scale insects or fungal microorganisms which might otherwise mar the appearance or cause later spoilage of the fruit. Such spray washing may occur in conjunction with treatment of fruit with special solutions, usually water soluble, as described, for example, in U.S. Pat. Nos. 4,990,351 (Orman, et al); 5,007,335 (Orman, et al); and 5,148,738 (Orman, et al)--all assigned to Sunkist Growers, Inc.
Typically, the fruit are loaded onto a brush bed conveyor system which aligns the fruit into the linear pockets between elongated cylindrical brush rollers, which are aligned transversely to the movement of the conveyor. A system of nozzles on a fixed manifold located above the brush bed rollers directs fluid onto the fruit passing below it. The rollers brush, scrub and rotate the fruit while the fruit is being simultaneously spray washed from above by the fixed spraying system. As described in one or more of the aforementioned patents, the solution may be filtered and recirculated for conservation and economy.
In order to provide sufficient rotation and exposure of the fruit to the scrubbing and spray washing action, the number of fruit which can be placed on the brush bed must necessarily be limited. A certain degree of open space must be provided to allow the fruit to turn and to be freely advanced down the brush bed.
It is inherent in the nature of the brush bed handling of the fruit that queuing of the fruit may exist with spaces between groups of fruit being urged down the brush bed. Typically, in order to maximize the effectiveness of the spray, the spray apparatus will have a coverage that completely extends over the entire washing area of the brush bed. Thus, water and/or solution is sprayed into areas of the brush bed which are empty because of the queuing of the fruit or the necessary open space which must be provided for proper fruit handling, with the result that the spray solution and, more typically, the power required to pump the solution can easily be wasted.
Furthermore, the fruit is loaded onto the brush bed from a hopper in a random manner. Large open areas of the brush bed can occur at any time during the washing process, particularly at the entry portions of the bed. These areas receive spray even if there is no fruit being loaded onto the brush bed, as long as there is any fruit on the brush bed which needs to be washed.
Finally, particularly in scale removal, it is desirable for a high-pressure (i.e., forceful, intensive) spray to cover the entire surface of each fruit, preferably several times.
Therefore, what is needed is an apparatus and method wherein the spray washing--particularly high-pressure spray washing--of fruit or other objects on brush beds may be more efficiently and effectively performed, in terms of minimizing the amount of wasted fluid and unnecessarily expended power used in pumping, and also in terms of improving the coverage of objects by the spray.